// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_NATIVE_LIBRARY_H_
#define BASE_NATIVE_LIBRARY_H_

// This file defines a cross-platform "NativeLibrary" type which represents
// a loadable module.

#include <string>

#include "base/base_export.h"
#include "base/strings/string_piece.h"
#include "build/build_config.h"

#if defined(OS_WIN)
#include <windows.h>
#elif defined(OS_MACOSX)
#import <CoreFoundation/CoreFoundation.h>
#endif // OS_*

namespace base {

class FilePath;

#if defined(OS_WIN)
using NativeLibrary = HMODULE;
#elif defined(OS_MACOSX)
enum NativeLibraryType {
    BUNDLE,
    DYNAMIC_LIB
};
enum NativeLibraryObjCStatus {
    OBJC_UNKNOWN,
    OBJC_PRESENT,
    OBJC_NOT_PRESENT,
};
struct NativeLibraryStruct {
    NativeLibraryType type;
    CFBundleRefNum bundle_resource_ref;
    NativeLibraryObjCStatus objc_status;
    union {
        CFBundleRef bundle;
        void* dylib;
    };
};
using NativeLibrary = NativeLibraryStruct*;
#elif defined(OS_POSIX)
using NativeLibrary = void*;
#endif // OS_*

struct BASE_EXPORT NativeLibraryLoadError {
#if defined(OS_WIN)
    NativeLibraryLoadError()
        : code(0)
    {
    }
#endif // OS_WIN

    // Returns a string representation of the load error.
    std::string ToString() const;

#if defined(OS_WIN)
    DWORD code;
#else
    std::string message;
#endif // OS_WIN
};

struct BASE_EXPORT NativeLibraryOptions {
    NativeLibraryOptions() = default;
    NativeLibraryOptions(const NativeLibraryOptions& options) = default;

    // If |true|, a loaded library is required to prefer local symbol resolution
    // before considering global symbols. Note that this is already the default
    // behavior on most systems. Setting this to |false| does not guarantee the
    // inverse, i.e., it does not force a preference for global symbols over local
    // ones.
    bool prefer_own_symbols = false;
};

// Loads a native library from disk.  Release it with UnloadNativeLibrary when
// you're done.  Returns NULL on failure.
// If |error| is not NULL, it may be filled in on load error.
BASE_EXPORT NativeLibrary LoadNativeLibrary(const FilePath& library_path,
    NativeLibraryLoadError* error);

// Loads a native library from disk.  Release it with UnloadNativeLibrary when
// you're done.  Returns NULL on failure.
// If |error| is not NULL, it may be filled in on load error.
BASE_EXPORT NativeLibrary LoadNativeLibraryWithOptions(
    const FilePath& library_path,
    const NativeLibraryOptions& options,
    NativeLibraryLoadError* error);

#if defined(OS_WIN)
// Loads a native library from disk.  Release it with UnloadNativeLibrary when
// you're done.
// This function retrieves the LoadLibrary function exported from kernel32.dll
// and calls it instead of directly calling the LoadLibrary function via the
// import table.
BASE_EXPORT NativeLibrary LoadNativeLibraryDynamically(
    const FilePath& library_path);
#endif // OS_WIN

// Unloads a native library.
BASE_EXPORT void UnloadNativeLibrary(NativeLibrary library);

// Gets a function pointer from a native library.
BASE_EXPORT void* GetFunctionPointerFromNativeLibrary(NativeLibrary library,
    StringPiece name);

// Returns the full platform specific name for a native library.
// |name| must be ASCII.
// For example:
// "mylib" returns "mylib.dll" on Windows, "libmylib.so" on Linux,
// "libmylib.dylib" on Mac.
BASE_EXPORT std::string GetNativeLibraryName(StringPiece name);

} // namespace base

#endif // BASE_NATIVE_LIBRARY_H_
